Converter rating optimisation for a brushless doubly fed induction generator

This article studies the converter rating requirement of a Brushless doubly-fed induction generator (DFIG) for wind turbine applications. Practical constraints such as the generator torque-speed requirement, reactive power management and grid low-voltage ride-through (LVRT) are considered. Experimental data have been used to obtain a realistic system model of a Brushless DFIG in a wind turbine. The study shows that there is a minimum converter rating, dependant on operating point, but this may not be achievable without machine derating. The use of a capacitor bank enables the converter ratings to be reduced without compromising the machine´s performance. The effect of the machine´s leakage inductance on the interplay of LVRT, achievable system power factor, converter rating and losses is investigated.